From the game's
flyer: "...is a futuristic world of brilliant
colors and imaginative creatures.

It's formations
of alien birds, bats and winged beasts that must be destroyed by
the fighter ship in fierce outer space combat. It's bonus
challenges and feats of flight and daring. It's non-stop action,
excitement...and profit...all in a universal conversion kit!

Using the rapid
fire gun too often means loosing charges which can be
re-energized only by on-target shooting with the dual space
cannons. The larger-than-life mutant space birds, genetically
bred by the Exerions and on the attack with heat-seeking
missiles, take eight hits to be destroyed... and take on a bright
rainbow of changing colors when hit! And the EXERION adventure
becomes more and more challenging as play continues!..."...need
I say more ? ; )

The space craft moves
in a pseudo 3D colorful background which changes very often when
a different attack wave comes up. There are lots of scenes and
alien spacecrafts to shoot, showing a very high AI from the early
stages. The game behaves in a very cunning way and some times
cheats the player !

There is a notorious
bug. In the challenge stage, if you shoot all 40 aliens you
normally get a bonus charge of 60. Sometimes a red hydra comes
out during this stage. If you shoot it and all 40 aliens, you get
a total of 41. The game seems to fail the test of 'hits=40' and
only gives you a bonus charge of 41. Pretty obscure I admit, but
there you go!

The player has to be
extremely precautious when the purple vessels come up, cause they
move randomly and very often appear surprisingly from the bottom
of the screen.

Part of this game was
later used in the fifth stage of "The Game Paradise".
The stage is called "23bit CPU captured by 8bit CPU".

Found your Exerion website; very nicely done, thank you. :-)
You did ask for experiences with Exerion, so here goes...

My experience with Exerion was that I installed the game (as a
conversion kit) into a Nintendo upright cabinet; possibly Donkey Kong or
Donkey Kong Jr.

We probably had the only Exerion on this planet with colored objects on
a WHITE background, because Nintendo monitors have negative (-) sync and
negative (-) R, G, and B connections. So any signal you connect to that
monitor will appear with all of its colors reversed. It wasn't until
many months later that I realised that Exerion was supposed to have a
black background (it's a SPACE GAME, hello!!!), and that the signals on
Nintendo monitors could easily be inverted with a simple and inexpensive
IC chip (a 7808 hex inverter, I believe).

As an addendum, I installed the Exerion
conversion when I worked as a
video game technician for Norm's Vending in Juneau Alaska around 1983.
If I remember correctly, it was one of the first conversions I did; and
somewhere around here, I have a photograph of the finished Exerion in a
light blue Nintendo cabinet.

Note the white "sky"; which proves beyond
a shadow of a doubt that the game inverted all of the colors because Nintendo
monitors have that silly backward sync and RGB inputs.
FWIW: I have a web page about a coin-op upright game I used to have:
http://ledlights.home.att.net/arcade.htm
Some of my photographs were used on KLOV (the site I found the link to
your Exerion website); so don't be concerned if some of those
photographs somehow look familiar

Thank you again for your wonderful Exerion website, and have a fantastic
weekend - or what's left of it anyway.

I too
played this game to death as a teenager and now play it on my 50" TV via my
Xbox. The Charge bug where you only get credited 41 ammo is due to hitting the
bomb that the hydra drops, you can kill the hydra but don't hit the bomb if it
drops one as this counts as a hit. You can however kill the hydra without
hitting the bomb it drops and you will still get credited the full 60 charge.